On 5/1/2014 10:37 AM, Dennis Cote wrote: > On Thursday, May 1, 2014 8:51:36 AM UTC-6, Gerald wrote: >> >> No. If they were connected, they could be used. They do not require the >> PRU to drive them. >> >> > Can you explain how the hardware is setup to assign these UART pins to > either PRU or the CPU? > > I have been looking through the TI TRM and AM335x datasheet, and at the TI > Pin Mux Utility trying to figure this out. The TRM has very little to say > about the PRU. > > The fact that I can have the CPU drive UART0 on one set of I/O pins and the > PRU driving PR1_UART0 on a different set of I/O pins seems to imply that > UART0 is not the same peripheral as PR1_UART0. So how do I setup the > PR1_UART0 pins to connect to the UART0 signals? The Pin Mux Utility shows > them as separate peripheral interfaces.
UART0 and PR1_UART0 are totally different chunks of hardware. Do not get confused by the fact that they both have "UART0" in the name, they are *NOT* the same. You control the selection of PR1_UART0 pin functions the same way you control any other special functions: make a device-tree overlay and load the appropriate settings into the pinmux registers. > It turns out that using the PRU might make sense in my application. To do > this I would have to abandon using the AM335x I2C peripherals and add some > SPI to I2C bridge parts to drive the I2C connected peripherals, but I > suspect that would involve a lot of custom driver development to allow > these bridged I2C buses to operate like the standard I2C buses. I would > also have to develop some kind of IPC link between the CPU and PRU. There is an rproc interface for the PRU if that helps. See the example BB-BONE-PRU-0[2-4] device tree overlays. -- Charles Steinkuehler char...@steinkuehler.net -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
